Fluid diode



T. D. READER April 2, 1968 FLUID DIODE Filed Dec. 23, 1964 III j/I/IIII INVENTOR TREVOR DRAKE READER United States Patent ()flice 3,375,842 FLUID DIODE Trevor Drake Reader, King of Prussia, Pa., assignor to Sperry Rand Corporation, New York, N.Y., a corporation of Delaware v Filed Dec. 23, 1964, Ser'. No. 420,557 9 Claims. (Cl. 137--81.5)

The invention hereinafter described and claimed has to do with fluid flow control devices, but more particularly to fluid diodes. With still more particularity however, the invention relates to the combination of a pure fluid diode with an elect-ro-fluid power transducer for moving fluid through the diode.

It is the primary object of the invention to provide a fluid control device comprising a pure fluid diode having low impedance to fluid flow in one direction therethrough and high impedance to fluid flow in the opposite direction therethrough, and characterized by its improved efficiency over known devices of this kind.

Another object of the invention is to provide a fl-uid control device wherein an alternating or pulsating fluid flow is rectified to produce a substantially unidirectional flow from its output.

A further object is to provide a simple means for converting A.C. electrical power into D.C. fluid power.

In accordance with the above objects and first briefly described, the invention comprises a pure fluid diode having a low impedance fluid flow path and a high impedance fluid flow path, and an electro-fluid power transducer which provides .an alternating or pulsating fluid flow into the diode. The construction and arrangement of the device is 'su-ch that flow in the low impedance direction is rectified to produce a substantially even unidirectional or DC. flow of fluid from its output, while flow in the high impedance direction is choked off by sudden and disruptive expansion, and by being directed back upon itself.

In the drawings:

FIGURE 1 is a plan view of a ing to the invention;

FIGURE 2 is a sectional view taken along line 22 of FIGURE 1;

FIGURE 3 is a somewhat diagrammatic sectional View of a fluid control device embodying the invention; and

FIGURE 4 is a simplified fragmentary view showing a modified form of the invention.

Referring now to the details of the drawings and first to FIGURE 1, it is seen that the pure fluid diode comprises a body of some fluid impervious material having formed therein a fluid flow channel generally designated by the numeral 12. In accordance with customary practice, and .as seen more clearly in FIGURE 2, the body 10 may be formed by three laminae 14, 16 and 18 of metallic, plastic, or other suitable material tightly sealed together by a suitable adhesive, or by screws. The diffusers could equally well be of circular cross-section. For the purpose of illustration the laminae are shown as being of a transparent plastic material. Prior to sealing the laminae together, lamina 16 was cut out or otherwise formed with the channel 12 including a fluid inlet 20 and a fluid outpure fluid diode accordlet 22.

Fluid under predetermined pressure, higher than atmospheric pressure, entering inlet 20 to flow through the unrestricted straight channel portion 24 is turned in the op posite direction by the curved wall 26 at the end 27 of 3,375,842 Patented Apr. 2 1968 channel portion 24 and into nozzle 28. The restriction at the nozzle accelerates the flow through the short straight section 29 and into the mid-channel section. 30 which is of gradually increasing cross-sectioual area, and which forms the first diffusion stage of the diode. As the fluid flows through this section it gradually expands or diffuses almost to its full static pressure by the time it reaches the end 32 of this section.

The curved end wall 33 of this channel section returns the flow to its original direction and into curved nozzle 34. The restriction at this nozzle accelerates the flow through straight section 35 into channel section 36 which is also of gradually increasing cross-sectional area and forms the second stage of the diode. In this section the fluid again is permitted gradually to expand or diifuse as it approaches the straight section 38 from which it is discharged through outlet 22 as a substantially unidirectional flow. Because of the gradual diffusion of the fluid as it passes through the channel sections 30 and 36, no eddy currents are produced and flow through them is smooth and easy.

In the high impedance or hard flow path-reverse to that described above-back flow and poor diffusion chokes off the flow. In this direction, diflusion of the fluid from the nozzles 34 and 28 into the unrestricted ends of the channel sections would be sudden and disruptive, causing eddies and backflow in the regions 32 and 27. This difliculty is compounded by the cusps '40 and 42 which turn the high speed flow from nozzles 34 and 28 back upon itself thus to choke off the output flow from the nozzles. If desired, channel Section 24 may be formed as indicated by the broken lines 43, thus forming it into a diode configuration.

Now with reference to FIGURE 3 it is seen that the diode 10 may form a part of a novel fluid control device wherein an alternating or pulsating fluid flow is provided to the diode by an electro-fluid power transducer 44.

The transducer 44 comprises a speaker or voice coil 46 for vibrating or oscillating a bellows 48 to produce an alternating fluid flow through the nozzle 50 into the diffuser section 52 forming the first stage of the diode 10. It will be noted in this form of the invention that the diode has three stages of alternating .acceleration and progressive diffusion instead of the two shown in FIGURE 1.

More specifically, the transducer comprises the bellows 48 suitably attached to the wall 56 of the diode structure, with its centrally located outlet aperture 58 aligned with the inlet 60 formed by the inwardly curving throat 62 of nozzle 50. The diode inlet or receiver 64 is aligned with nozzle 50 across a gap 66 which is open to atmosphere through conduits 68. The opposite wall 70 of the bellows is somewhat rigid or stiff and has a sleeve 72 attached to its central portion. Wrapped around and carried by the sleeve is an electrically conductive coil 74, the terminals 76 and 78 of which are connected to a suitable source of alternating current (not shown) of fifty or sixty cycles, for example. The coil is positioned to be influenced by the magnetic field supplied by the poles of the permanent magnet 81. The bellows is actuated by the interaction of the magnetic field of the permanent magnet and I the alternation of the direction of electric current in the coil.

In its operation: coil 74 is connected to a source of AC. power (50 or 60 c.p.s., for example) through leads 76 and 78 to oscillate the sleeve 72 thus to effect alternate suction and compressions movements or strokes of the bellows to produce a changing volume in the bellows chamber.

On the suction stroke, air flows into the bellows chamber mainly by way of conduits 68 which offer less restriction to fluid flow than does the restricted diode inlet 64. On the alternate compressions strokes, air from the bellows chamber is ejected at high velocity from nozzle 50 across the gap 66 to enter diffuse-r channel 52 of the diode through inlet receiver 64.

This alternating fluid flow into diode is successively subjected to gradual diffusion and high speed acceleration in each diffusion channel 52, and 36, as described in connection with FIGURE 1, thus producing a substantially smooth unidirectional flow at diode outlet 22.

If desired, a shock tank 82 may be connected to channel 38 through passageway 84. The walls of the tank consist of an elastic bellows permitting it to meet the required volume of the tank under differing pressure condi tion in the channel. The pressure built up in tank 82 serves to further smooth out the pulsating fluid flow by providing fluid to the flow on the low side of the fluid pulse, acting similarly to a capacitor in a corresponding electronic circuit.

Thus it is seen that a fluid control device, as shown in FIGURE 3, provides half wave rectification of alternating fluid flow from an electro-fluid power transducer actuated at A.C. power supply frequency to present a smooth D.C. fluid flow at the outlet of the device.

Full wave rectification may be obtained by providing a plurality of transducers. By way of example, a pair has been shown in FIGURE 4 operating 180 out of phase. In other words one transducer is exhaling while the other is inhaling.

In this form of the invention the bellows 90 is divided into two chambers 92 and 94- by a substantially rigid center wall 96. The end walls 98 and 100' are secured to fixed structure 102 having inlet/ outlet apertures 104 and 106 into the chambers 92 and 94 respectively.

Fluid conduits represented by broken lines 108 and 110 connect apertures 104 and 106 to passageways or nozzles 112 and 114 respectively of an exclusive fluid OR gate 116. The passageways 112 and 114 are aligned with the receiving inlet 118 of the diode 120, which may be of the same construction shown in FIGURE 3. The passageways preferably have diverging walls leading to the belvlows chambers thus to diffuse the fluid and provide smooth flow in the intake stroke.

The dividing wall 96 of the bellows is connected by a rod 122 to the sleeve 124 of the voice coil transducer 126, also similar to that shown in FIGURE 3. The connecting rod 122 passes through the fixed structure 102 where it is provided with a flexible seal 128.

In its operation, under the influence of an A.C. power supply, and the permanent magnet 130, the voice coil will oscillate wall 96 alternately enlarging and decreasing the volume of chambers 92 and 94, thereby alternately sucking air into and driving air out of the chambers. Movement of wall 96 to the right, as illustrated by the broken line 132 in FIGURE 4, sucks air into chamber 92 from atmosphere by way of conduit 134, passageway 112as indicated by the arrowsthrough conduit 108 and inlet/outlet aperture 104. At the same time air in chamber 94 is driven at high velocity through its inlet/ outlet opening 106, conduit 110, passageway (now nozzle) 114 into diode receiver 118. On the return stroke of rod 122, the flow is reversed and the diode receives a pulse of air from the passageway (now nozzle) 112, while air from atmosphere is sucked into chamber 94 by way of conduit 136, passageway 114, conduit 110', and inlet/ outlet opening 106.

It will be understood from the above that flow to the diode may also be provided by a plurality of individual transducers operating in sequence to deliver fluid pulses to the diode receiver through exclusive OR gates having a nozzle for each bellows. Suitable circuitry may be provided to actuate the bellows by electrical current whose phase angles differ by where n equals the number of individual bellows.

The embodiments of this invention in which an exclusive property or privilege is claimed are defined as follows:

1. A fluid device comprising a body member having a channel therethrough formed to act as a fluid diode presenting relatively low impedance to fluid flow therethrough in the easy direction and relatively high impedance to fluid flow therethrough in the opposite direction, said channel having inlet and outlet openings, a bellows means for entering pulsating fluid flow into said inlet opening, said bellows means including a bellows and a means for oscillating the bellows alternately with suction and compression strokes, and wherein said diode inlet opening is restricted and said bellows has a common inlet/ outlet aligned with said restricted diode inlet opening across an unrestricted gap open to atmospheric pressure whereby, upon the suction stroke of said bellows, air is drawn into the bellows chamber through said gap from atmosphere, and upon its compression stroke air is driven from the bellows at high velocity across said gap and into said diode inlet opening.

2. A fluid diode device according to claim 1 wherein said restricted diode inlet opening comprises the nozzle of a first diffusion chamber of gradually increasing crosssectional area terminating in a curved wall forming the throat of a restricted nozzle having a short straight section leading to a second chamber of gradually increasing crosssectional area and extending in a different direction, said second chamber terminating in a curved wall forming the throat of another nozzle having a short straight section leading into a third chamber of gradually increasing cross-sectional area extending in a different direction from said second chamber and terminating at the outlet opening of said channel.

3. A fluid diode device according to claim 2 wherein said curved walls are formed with cusps for directing flow of fluid in the opposite direction back upon itself at said nozzles thereby to choke off such flow.

4. A fluid diode device according to claim 3 and further including a shock tank opening into a channel portion adjacent said outlet opening.

5. A construction according to claim 4 wherein said shock tank is a flexible bellows.

6. A fluid diode device according to claim 1 wherein said bellows means includes a plurality of bellows each successively providing a high velocity pulse of fluid into the inlet of said diode, thus providing a substantially uniform fluid flow.

7. A fluid diode device according to claim 6 wherein said bellows means comprises a pair of bellows operated in opposite phase by a voice coil when the coil is connected to a source of A.C. power.

8. A fluid diode device according to claim 1 wherein said bellows means includes a plunality of voice coil openated bellows, each driven by currents whose phase angles differ by channel t-herethrough formed to act as a fluid diode presenting relatively low impedance to fluid flow therethrough in the easy direction and relatively high impedance to fluid flow therethrough in the opposite direction, said channel having inlet and outlet openings, said inlet opening being restricted, a pulsating fluid source having alternately suction and compression strokes, said source having a common inlet/outlet aligned with the inlet of said channel across an unrestricted gap open to atmospheric pressure, whereby upon the suction stroke air is drawn into the pulsating source through said gap and upon compression air is driven from the pulsating source at high velocity across said gap and into said channel inlet.

References Cited UNITED STATES PATENTS Tesla 137-815 Lindenoth 137-815 Kantrowitz 138-37 Spar-row 137-815 Hatch 137-815 M. CARY NELSON, Primary Examiner. W. CLINE, Assistant Examiner. 

9. A FLUID DEVICE COMPRISING A BODY MEMBER HAVING A CHANNEL THERETHROUGH FORMED TO ACT AS A FLUID DIODE PRESENTING RELATIVELY LOW IMPEDANCE TO FLUID FLOW THERETHROUGH IN THE EASY DIRECTION AND RELATIVELY HIGH IMPEDANCE TO FLUID FLOW THERETHROUGH IN THE OPPOSITE DIRECTION, SAID CHANNEL HAVING INLET AND OUTLET OPENINGS, SAID INLET OPENING BEING RESTRICTED, A PULSATING FLUID SOURCE HAVING ALTERNATELY SUCTION AND COMPRESSION STROKES, SAID SOURCE HAVING A COMMON INLET/OUTLET ALIGNED WITH THE INLET OF SAID CHANNEL ACROSS AN UNRESTRICTED GAP OPEN TO ATMOSPHERIC PRESSURE, WHEREBY UPON THE SUCTION STROKE AIR IS DRAWN INTO THE PULSATING SOURCE THROUGH SAID GAP AND UPON COMPRESSION AIR IS DRIVEN FROM THE PULSATING SOURCE AT HIGH VELOCITY ACROSS SAID GAP AND INTO SAID CHANNEL INLET. 